Dispensing systems for dispensing curable sealants are well known in the art. There are a variety of methods for applying sealant to a fastener using a cap. The methods involve applying the sealant and then shaping it with a cap over the fastener or injecting the sealant into a cap encasing the fastener. These methods require precise metering of the sealant either around the fastener prior to placing the cap around the sealant, or into a cap before placing the cap and sealant over fasteners. These methods are costly and impractical. Moreover, these methods do not provide consistent results.
Preformed sealant caps which are filled with uncured sealant immediately prior to application on the fastener are subject to similar inefficiencies. This extra step of filling the cap with uncured sealant makes application of the sealant on the fastener cumbersome. The typical practice involved applying sealant on many fasteners at one time. The extra step of filling caps complicates the application and adds to the length of time required to apply the sealant on fasteners throughout the substrate. The fact that the sealant cures within a fixed period of time after dispensing complicates dispensing the sealant prior to the application to the fastener.
Furthermore, many manufacturers manually seal nut plate fasteners by extruding and tooling the sealant over the fastener. However, this is a difficult and time-consuming process because many of the fasteners are located in locations that are difficult to access, making it technically difficult to access and seal the fasteners. Additionally, it is often difficult to control the sealant thickness that is applied to the fasteners.
Finally, fasteners are typically manufactured as a series, with fasteners in each series having specific base dimensions and being provided in a range of shaft lengths. Accordingly, preformed sealant caps are typically manufactured for use with each shaft length for each series. This increases production costs.
There is a need, therefore, for a sealant that addresses the inefficiencies and complications of the existing materials.